Grade needed to pass calculator

The classic end-of-term question: "what do I need on the final to pass?" It comes from the weighted-average idea. If the final has weight p (as a fraction), the rest of the grades weigh 1 − p.

needed grade = (target − current_avg × (1 − p)) ÷ p

Step-by-step example

I need an average of 6 to pass. My average on the other assessments is 5, and the final is worth 40% (p = 0.4):

1. Contribution so far: 5 × 0.6 = 3.0
2. Still need to reach 6: 6 − 3.0 = 3.0
3. Grade on the final: 3.0 ÷ 0.4 = 7.5

Reading the result

• Result ≤ 10: achievable — that's the minimum grade on the final.
• Result > 10: even a perfect final isn't enough on its own.
• Result ≤ 0: you've already passed, even with a zero on the final.